Blast Cleaninng of Steel Ships Using Recycled Glass

7/31/2019 Blast Cleaninng of Steel Ships Using Recycled Glass

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9 November 2005 Ship Repair & Conversion 2005 [email protected]

Blast Cleaning of Ship Steelusing Re-cycled Glass

Professor George Bruce


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Content

Background

Blast Cleaning Media

Legislation & Standards

Project Blasting Trials

Results

Conclusions


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Background

The Importance of Blast Cleaning

Control by Shipyard

Shipowner Coating Company

Critical in good Coating of Steel


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Project Objectives

Testing of Re-cycled Glass Materials (RGM)

Blasting Capability Productivity

Surface Condition Cost Comparison


5/299 November 2005 Ship Repair & Conversion 2005 [email protected]

Blasting Media

Natural minerals - silica sand, garnet,olivine

Manufactured media - steel shot, glass

grit, alumina, plastic pellets or beads, solidcarbon dioxide, sodium bicarbonate

Mineral slag - copper slag, nickel slag,

iron slag and coal slag

Organic media - corn cobs, nut shells,

starch grains



Ship Blasting Media

Sand Health and Safety Hazard

Grit Copper Slag, Disposal Costs

Steel Shot Expensive, Closed System

Garnet High Quality but Expensive

UHP Water Lower capability

RGM To be tested



UK Legislation

Landfill Tax will double disposal costs

EU Packaging Directive Glass Recycling

Kyoto Summit Emissions Reduction

Statutory Re-cycling Targets

Trying to anticipate future legislation



Working Standards

Steel Surface Finish to SA 2.5 Standard

Depends on initial sub-strate

50-75 microns ideal for coating



Previous Results

For Epoxy coating:

Glass abrasive cleaned - 11.6 m2/hr

Copper Slag cleaned 9.5 m2/hr

Nickel Slag cleaned 8.0 m2/hr

Glass abrasive consumed 40.9 kg/m2

Copper Slag consumed 76.7 kg/m2

Nickel Slag consumed 74.3 kg/m2



Potential Benefits of Glass

Inert Material

No Heavy Metals (unlike Copper Slag)

No Salts Reduced Corrosion

No Free Silica



Project Blasting Trials

Initial Trials

Small Samples in Controlled Conditions

Establishing Baseline Comparisons

Initial Shipyard Trials

Small Samples in Shipyard Conditions

Establishing Media Capability in Shipyards Full Scale Trials

Blasting Marine Structures



Initial Controlled Trials

Tests on Steel Plates

Some Pipes

Beams and other Structural Sections

Established the capability of RGM

Similar Performance to Grit



Initial Shipyard Trials

Various Steel Plates from Ships

RGM Compared to UHP

RGM used wet as well as dry

Compared in 2nd Shipyard to Copper Slag

Samples blasted, inspected and coated



Plates prior to Blasting


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RGM Closeup


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RGM Blasting of Samples


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Steel Samples after Blasting


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Full Scale Shipyard Trials

Mooring Barge

Heavily Corroded Comparison between RGM and UHP

Mooring Pontoon

Heavily Coated

Comparison between RGM and Copper Slag


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Mooring Pontoon before Blasting


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Mooring Barge before Blasting


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Shipyard Trial Results (1)

Abrasive Dry RGM Wet RGM Wet RGM UHPSize (mm) 0.75-1.5 0.75-1.5 0.75-1.5 N/A

Surface

cleanliness

SA 2.5 SA 2.5 SA 2.5 SA 2.5

Roughnessm

2233 2207 2207 Could notbe measured

Dust 2 1 1 1

Productivity

(m/h)

4.19 1.62 4.63 5.15

Specific GritConsumption

(kg/m)

19.33 115.74 42.74 186.48 lWater

Table 1. Shipyard 1 Full Scale Trials with different media


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Blasted Mooring Barge


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Shipyard Trial Results (2)

Abrasive Dry RGM Dry RGM Copper Slag Copper SlagSize (mm) 0.75 1.5 0.75 1.5 1.4 2.5 1.4 2.5

Surface

cleanliness

SA 2.5 SA 2.5 SA 2.5 SA 2.5

Roughness

m

95 2415 202 2396

Dust 3 2 3 2

Productivity(m/h)

12.649 12.43 10.89 12.87

Specific GritConsumption

(kg/m)

45.21 46.02 35.11 29.72

Table 2. Shipyard 2 Full scale trials with different media


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RGM Blasting of Pontoon


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Pontoon after Blasting


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Full Scale Shipyard Trials

Comments

RGM showed a steep learning curve

Wet RGM was not very successful RGM gave improved appearance

RGM is a Capable Process

Further Monitoring is in Progress


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Conclusions

RGM Performance is Comparable to Other

Media RGM is Equally Capable of Surface

Preparation for Coating

RGM has similar productivity to UHP

Supplies of RGM at acceptable cost are

essential

Further work on disposal is required


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Q & A

George Bruce

Blast Cleaninng of Steel Ships Using Recycled Glass

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